One type of known tire building apparatus comprises drum means that includes an intermediate drum assembly and end drum assemblies which in starting or initial positions thereof provide a substantially cylindrical surface for supporting tire carcass material in the form of a cylinder. After disposition of tire carcass material around the intermediate drum assembly, tire beads are pre-positioned by ring means and locked in place, the ring means are retracted, the intermedite drum assembly is expanded to form the tire carcass material into substantially torus configuration approximating that of a completed tire, breaker and thread components are applied to the crown portion of the tire carcass, and the ring means in association with inflatable ply turn-up bag means are employed to turn plys up and apply tire sidewall or other components to the sidewall portions of the formed tire carcass.
Known tire building apparatus of the character noted do not conveniently provide for precise location of the ring means in predetermined inward bead set positions.